Transoral Robotic Surgery Without Adjuvant Therapy: A Systematic Review and Meta-Analysis of the Association Between Surgical Margins and Local Recurrence.

Background: Transoral robotic surgery (TORS) is increasingly employed in the management of oropharyngeal cancer without adjuvant treatment. Attaining safe surgical margins is paramount to preventing local recurrence (LR), but the necessary surgical margin dimension remains contentious.Methods: Systematic review and meta-analysis of studies reporting margin status and LR following TORS without adjuvant therapy for primary OPSCC.Results: The search identified 269 articles and 11 were selected for inclusion, with 406 patients included in the meta-analysis. Heterogeneity was noted in the definition of "close" margins. Random-effects pooled rate of positive margins was 7 % (95 % CI 0.04-0.12, I-2 = 54 %, p = 0.02) and close margins was 7 % (95 % CI 0.02-0.27, I-2 = 86 %, p=<0.01). The random-effects overall rate of LR was 6 % (95 % CI 0.04-0.10, I-2 = 11 %, p = 0.35), 13 % (95 % CI 0.02-0.620, I-2 = 0 %, p = 1.0) after a positive margin, and 3 % (95 % CI 0.03-0.24, I-2 = 23 %, p = 0.26) after a close margin. Odds ratio (OR) for LR indicated higher risk of LR for positive compared to close margins (7.5; 95 % CI 1.31-42.91, I-2 = 0 %, p = 0.51), and a slightly lower risk of LR between close and negative margins (2.22; 95 % CI 0.67-7.38, I-2 = 0 %, p = 0.8). A lack of frozen-section analysis (OR 2.91, p = 0.36) and HPV-negative disease (OR 1.68, p = 0.03) were associated with an elevated risk of LR.Conclusions: TORS as a standalone treatment is associated with low rates of LR; however, the literature is hampered by considerable heterogeneity in margin definitions. Larger multicentre studies are required to determine the precise margin cut-off required for oropharyngeal tumours managed with TORS alone.